sorry, but was is a "peen"?
Furthermore, my shock don't have any compression or rebound adjustement. (yes, shock on road bike can be very "simple"...).
Even if I have release the pressure in the bladder through the schreader valve, there is still some air in the shock. I know that, because when the shock is upside down, I can move the shaft very easily at the end of the stroke. I deduce that the valve is moving in air instead of oil.
Hope you understand me.